Microsatellite analysis of genetic diversity in sweetpotato varieties from Latin America.

Abstract

tropical America. The sweetpotato gene bank maintained at CIP now contains 5526 cultivated accessions from 57 countries, of which 2589 are from Latin America. Understanding the diversity in the distribution of this germplasm is essential for its rational management and use. In the present study, we ana-lyzed a group of sweetpotato varieties from Latin America using simple-sequence repeat (SSR) markers. Twelve SSR primer pairs with di-nucleotide tandem repeats were screened. Six primer pairs that generated scorable allelic information were used to type the 113 varieties. The six SSR loci revealed a total of 70 alleles, with allele size ranging from 102 base pairs to 173. Both the richness and the evenness of the alleles show a significant geographical pattern in the Latin American sweetpotato gene pool. Mesoamerica ranks the highest in terms of total number of alleles, number of region-specific alleles, and actual heterozygosity, whereas the region of Peru-Ecuador ranks the lowest on all three counts. This, together with our earlier findings based on AFLP analysis, strongly supports the hypothesis that